Figure 1.
Inhibition of nutrient intake by aversive tastants. (A) Schematic diagram of the Capillary Feeding (CAFE) assay. Eight individuals of the same sex are placed in each vial. Three capillaries are inserted through the foam cap and 50mM sucrose solution (positive control) or a 50mM sucrose solution supplemented with bitter tastant is aspirated into each capillary. Mineral oil is placed on the top of the capillary to prevent evaporation. Flies are allowed to feed for 24h in a closed humid chamber with 80% humidity. (B) The figure shows two representative examples for dose-dependent consumption of sucrose solution supplemented with bitter tastant, coumarin, and papaverine. Consumption of bitter tastants is represented as percentage of sucrose intake by offspring from the progenitor control line (y,w 1118 ; P{attP,y + ,w 3’}) crossed to the tubulin-GAL4 driver line. Arrows indicate the optimally discriminating bitter tastant concentrations selected for further experiments. Males are shown in grey bars and females in black bars.